scholarly journals Specificity and Redundancy of Profilin 1 and 2 Function in Brain Development and Neuronal Structure

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2310
Author(s):  
Marina Di Domenico ◽  
Melanie Jokwitz ◽  
Walter Witke ◽  
Pietro Pilo Boyl
Keyword(s):  
Actin Polymerization ◽  
Conditional Knockout ◽  
Brain Morphology ◽  
Actin Dynamics ◽  
Neuronal Structure ◽  
Knockout Mouse Model ◽  
Conditional Knockout Mouse ◽  
Neuronal Stem Cell ◽  
Neuronal Precursors ◽  
Redundant Functions

Profilin functions have been discussed in numerous cellular processes, including actin polymerization. One puzzling aspect is the concomitant expression of more than one profilin isoform in most tissues. In neuronal precursors and in neurons, profilin 1 and profilin 2 are co-expressed, but their specific and redundant functions in brain morphogenesis are still unclear. Using a conditional knockout mouse model to inactivate both profilins in the developing CNS, we found that threshold levels of profilin are necessary for the maintenance of the neuronal stem-cell compartment and the generation of the differentiated neurons, irrespective of the specific isoform. During embryonic development, profilin 1 is more abundant than profilin 2; consequently, modulation of profilin 1 levels resulted in a more severe phenotype than depletion of profilin 2. Interestingly, the relevance of the isoforms was reversed in the postnatal brain. Morphology of mature neurons showed a stronger dependence on profilin 2, since this is the predominant isoform in neurons. Our data highlight redundant functions of profilins in neuronal precursor expansion and differentiation, as well as in the maintenance of pyramidal neuron dendritic arborization. The specific profilin isoform is less relevant; however, a threshold profilin level is essential. We propose that the common activity of profilin 1 and profilin 2 in actin dynamics is responsible for the observed compensatory effects.

scholarly journals A Conditional Knockout Mouse Model Reveals That Calponin-3 Is Dispensable for Early B Cell Development

PLoS ONE ◽  
2015 ◽  
Vol 10 (6) ◽  
pp. e0128385 ◽  
Author(s):  
Alexandra Flemming ◽  
Qi-Quan Huang ◽  
Jian-Ping Jin ◽  
Hassan Jumaa ◽  
Sebastian Herzog
Keyword(s):  
Mouse Model ◽  
B Cell ◽  
Knockout Mouse ◽  
Cell Development ◽  
B Cell Development ◽  
Conditional Knockout ◽  
Knockout Mouse Model ◽  
Conditional Knockout Mouse

scholarly journals A dual role for integrin-linked kinase in platelets: regulating integrin function and α-granule secretion

Blood ◽  
2008 ◽  
Vol 112 (12) ◽  
pp. 4523-4531 ◽  
Author(s):  
Katherine L. Tucker ◽  
Tanya Sage ◽  
Joanne M. Stevens ◽  
Peter A. Jordan ◽  
Sarah Jones ◽  
...  
Keyword(s):  
Thrombus Formation ◽  
Dense Granule ◽  
Conditional Knockout ◽  
Knockout Mouse Model ◽  
Conditional Knockout Mouse ◽  
Fibrinogen Binding ◽  
Integrin Linked Kinase ◽  
Dense Granule Secretion ◽  
Granule Secretion

Abstract Integrin-linked kinase (ILK) has been implicated in the regulation of a range of fundamental biological processes such as cell survival, growth, differentiation, and adhesion. In platelets ILK associates with β1- and β3-containing integrins, which are of paramount importance for the function of platelets. Upon stimulation of platelets this association with the integrins is increased and ILK kinase activity is up-regulated, suggesting that ILK may be important for the coordination of platelet responses. In this study a conditional knockout mouse model was developed to examine the role of ILK in platelets. The ILK-deficient mice showed an increased bleeding time and volume, and despite normal ultrastructure the function of ILK-deficient platelets was decreased significantly. This included reduced aggregation, fibrinogen binding, and thrombus formation under arterial flow conditions. Furthermore, although early collagen stimulated signaling such as PLCγ2 phosphorylation and calcium mobilization were unaffected in ILK-deficient platelets, a selective defect in α-granule, but not dense-granule, secretion was observed. These results indicate that as well as involvement in the control of integrin affinity, ILK is required for α-granule secretion and therefore may play a central role in the regulation of platelet function.

scholarly journals Hormone-Responsive BMP Signaling Expands Myoepithelial Cell Lineages and Prevents Alveolar Precocity in Mammary Gland

2021 ◽  
Vol 9 ◽  
Author(s):  
Chunlei Shao ◽  
Pengbo Lou ◽  
Ruiqi Liu ◽  
Xueyun Bi ◽  
Guilin Li ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Myoepithelial Cells ◽  
Bmp Signaling ◽  
Conditional Knockout ◽  
Signaling Mechanism ◽  
Knockout Mouse Model ◽  
Conditional Knockout Mouse ◽  
Morphogenetic Protein ◽  
Organ Systems ◽  
Mammary Stem

Myoepithelial and luminal cells synergistically expand in the mammary gland during pregnancy, and this process is precisely governed by hormone-related signaling pathways. The bone morphogenetic protein (BMP) signaling pathway is now known to play crucial roles in all organ systems. However, the functions of BMP signaling in the mammary gland remain unclear. Here, we found that BMPR1a is upregulated by hormone-induced Sp1 at pregnancy. Using a doxycycline (Dox)-inducible BMPR1a conditional knockout mouse model, we demonstrated that loss of BMPR1a in myoepithelium results in compromised myoepithelial integrity, reduced mammary stem cells and precocious alveolar differentiation during pregnancy. Mechanistically, BMPR1a regulates the expression of p63 and Slug, two key regulators of myoepithelial maintenance, through pSmad1/5-Smad4 complexes, and consequently activate P-cadherin during pregnancy. Furthermore, we observed that loss of BMPR1a in myoepithelium results in the upregulation of a secreted protein Spp1 that could account for the precocious alveolar differentiation in luminal layer, suggesting a defective basal-to-luminal paracrine signaling mechanism. Collectively, these findings identify a novel role of BMP signaling in maintaining the identity of myoepithelial cells and suppressing precocious alveolar formation.

scholarly journals A Homeostatic Shift Facilitates Endoplasmic Reticulum Proteostasis through Transcriptional Integration of Proteostatic Stress Response Pathways

2016 ◽  
Vol 37 (4) ◽  
Author(s):  
Liam Baird ◽  
Tadayuki Tsujita ◽  
Eri H. Kobayashi ◽  
Ryo Funayama ◽  
Takeshi Nagashima ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Transcriptional Regulation ◽  
Ubiquitin Proteasome System ◽  
Conditional Knockout ◽  
Protein Homeostasis ◽  
Knockout Mouse Model ◽  
Conditional Knockout Mouse ◽  
Wide Range ◽  
Ubiquitin Proteasome ◽  
Inducible Systems

ABSTRACT Eukaryotic cells maintain protein homeostasis through the activity of multiple basal and inducible systems, which function in concert to allow cells to adapt to a wide range of environmental conditions. Although the transcriptional programs regulating individual pathways have been studied in detail, it is not known how the different pathways are transcriptionally integrated such that a deficiency in one pathway can be compensated by a change in an auxiliary response. One such pathway that plays an essential role in many proteostasis responses is the ubiquitin-proteasome system, which functions to degrade damaged, unfolded, or short half-life proteins. Transcriptional regulation of the proteasome is mediated by the transcription factor Nrf1. Using a conditional knockout mouse model, we found that Nrf1 regulates protein homeostasis in the endoplasmic reticulum (ER) through transcriptional regulation of the ER stress sensor ATF6. In Nrf1 conditional-knockout mice, a reduction in proteasome activity is accompanied by an ATF6-dependent downregulation of the endoplasmic reticulum-associated degradation machinery, which reduces the substrate burden on the proteasome. This indicates that Nrf1 regulates a homeostatic shift through which proteostasis in the endoplasmic reticulum and cytoplasm are coregulated based on a cell's ability to degrade proteins.

Anti-obesity effects of GIPR antagonists alone and in combination with GLP-1R agonists in preclinical models

2018 ◽  
Vol 10 (472) ◽  
pp. eaat3392 ◽  
Author(s):  
Elizabeth A. Killion ◽  
Jinghong Wang ◽  
Junming Yie ◽  
Stone D.-H. Shi ◽  
Darren Bates ◽  
...  
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Body Weight Gain ◽  
Association Studies ◽  
Conditional Knockout ◽  
Genome Wide Association Studies ◽  
Knockout Mouse Model ◽  
Conditional Knockout Mouse ◽  
Glucagon Like Peptide 1 ◽  
Treatment Of Obesity

Glucose-dependent insulinotropic polypeptide (GIP) receptor (GIPR) has been identified in multiple genome-wide association studies (GWAS) as a contributor to obesity, and GIPR knockout mice are protected against diet-induced obesity (DIO). On the basis of this genetic evidence, we developed anti-GIPR antagonistic antibodies as a potential therapeutic strategy for the treatment of obesity and observed that a mouse anti-murine GIPR antibody (muGIPR-Ab) protected against body weight gain, improved multiple metabolic parameters, and was associated with reduced food intake and resting respiratory exchange ratio (RER) in DIO mice. We replicated these results in obese nonhuman primates (NHPs) using an anti-human GIPR antibody (hGIPR-Ab) and found that weight loss was more pronounced than in mice. In addition, we observed enhanced weight loss in DIO mice and NHPs when anti-GIPR antibodies were codosed with glucagon-like peptide-1 receptor (GLP-1R) agonists. Mechanistic and crystallographic studies demonstrated that hGIPR-Ab displaced GIP and bound to GIPR using the same conserved hydrophobic residues as GIP. Further, using a conditional knockout mouse model, we excluded the role of GIPR in pancreatic β-cells in the regulation of body weight and response to GIPR antagonism. In conclusion, these data provide preclinical validation of a therapeutic approach to treat obesity with anti-GIPR antibodies.

scholarly journals A conditional knockout mouse model reveals endothelial cells as the principal and possibly exclusive source of plasma factor VIII

Blood ◽  
2014 ◽  
Vol 123 (24) ◽  
pp. 3706-3713 ◽  
Author(s):  
Scot A. Fahs ◽  
Matthew T. Hille ◽  
Qizhen Shi ◽  
Hartmut Weiler ◽  
Robert R. Montgomery
Keyword(s):  
Endothelial Cells ◽  
Mouse Model ◽  
Factor Viii ◽  
Knockout Mouse ◽  
Coagulation Factor ◽  
Conditional Knockout ◽  
Knockout Mouse Model ◽  
Conditional Knockout Mouse ◽  
Key Points ◽  
Plasma Factor

Key Points Endothelial cells are the predominant (and possibly exclusive) source of coagulation factor VIII. Hepatocytes do not contribute to plasma FVIII production.

scholarly journals Induced Arp2/3 Complex Depletion Increases FMNL2/3 Formin Expression and Filopodia Formation

2021 ◽  
Vol 9 ◽  
Author(s):  
Vanessa Dimchev ◽  
Ines Lahmann ◽  
Stefan A. Koestler ◽  
Frieda Kage ◽  
Georgi Dimchev ◽  
...  
Keyword(s):  
Conditional Knockout ◽  
Cell Periphery ◽  
Turnover Rates ◽  
Gene Encoding ◽  
Knockout Mouse Model ◽  
Membrane Ruffling ◽  
Conditional Knockout Mouse ◽  
Cell Type Specific ◽  
New Space ◽  
Filament Networks

The Arp2/3 complex generates branched actin filament networks operating in cell edge protrusion and vesicle trafficking. Here we employ a conditional knockout mouse model permitting tissue- or cell-type specific deletion of the murine Actr3 gene (encoding Arp3). A functional Actr3 gene appeared essential for fibroblast viability and growth. Thus, we developed cell lines for exploring the consequences of acute, tamoxifen-induced Actr3 deletion causing near-complete loss of functional Arp2/3 complex expression as well as abolished lamellipodia formation and membrane ruffling, as expected. Interestingly, Arp3-depleted cells displayed enhanced rather than reduced cell spreading, employing numerous filopodia, and showed little defects in the rates of random cell migration. However, both exploration of new space by individual cells and collective migration were clearly compromised by the incapability to efficiently maintain directionality of migration, while the principal ability to chemotax was only moderately affected. Examination of actin remodeling at the cell periphery revealed reduced actin turnover rates in Arp2/3-deficient cells, clearly deviating from previous sequestration approaches. Most surprisingly, induced removal of Arp2/3 complexes reproducibly increased FMNL formin expression, which correlated with the explosive induction of filopodia formation. Our results thus highlight both direct and indirect effects of acute Arp2/3 complex removal on actin cytoskeleton regulation.

Sign in / Sign up

Export Citation Format

Share Document